The objective of the proposed study is to develop a 6 degree-of-freedom pelvic assist manipulator (PAM) that will provide assistance and therapy to stroke patients as they relearn to stand from a sitting position, to balance while standing, and to walk. PAM will use low friction, lightweight pneumatic cylinders and will be designed to be as responsive and as lightweight as possible, while minimizing restrictions of movement of the patient. PAM will have an impedance control feature that will allow the patient to control their torso movement independently but will provide assistance when the torso trajectory deviates from a predetermined pattern, thereby providing the least amount of assistance necessary. The focus of this Phase I proposal will be to build the robot, test and modify a nonlinear pneumatic force control algorithm which has already been developed for different applications, and to develop the correct motion patterns that provide assistance and training for the sit to stand, balance and step training movements for stroke patients. In addition, a visual feedback system for the patient will be developed. There are many benefits to developing PAM for widespread use: For patients, PAM will offer accessibility to a novel training method that will improve their mobility and stepping capabilities, allowing them to participate in upright, aerobic exercise; for healthcare providers, PAM will provide a means of delivering effective therapy on a widespread basis and provide quantifiable results; and for research institutions and pharmaceutical companies, PAM will provide an automated system to train subjects and an effective way to test and measure intervention effects and rehabilitations protocols.